The term papañca occurs several times in the suttas, most notably in Majjima Nikaya 18, the Madhupindika Sutta (”Honeyball Discourse”, as it was named by the Buddha in response to Ananda's description of the "the sweet delectable flavour" of the discourse [MN 18.22]; given the Buddha's wry sense of humor, it may be conjectured that he also had in mind the particularly sticky nature of the concepts he was dealing with in the discourse.) In the discourse, the Buddha gives a curt and somewhat gnomic response to an equally curt and somewhat confrontative question from the wanderer Daṇḍapāni.

The Buddha's brief discourse concerned the mental processes that lead to violent actions—important stuff. It has to do with the tendency of our perceptions to take on a life of their own and trap our minds in an uncontrolled stream of imaginary constructs, untethered to the actual nature of the processes we observe. It was left to the elder bhikkhu Mahā Kaccāna to explain the Buddha's words to the sangha.

The process he describes begins with the arousal of consciousness—visual, auditory, olfactory, gustatory, tactile, and mental consciousness corresponding to the six sense bases as they are enumerated in Buddhist doctrine. Each sort of consciousness arises as a result of its associated sense organ and the objects that effect that sense organ; in the case of vision, for example, visual consciousness arises as a result of the presence of the eye and of visible forms. The three things together—consciousness, sense organ, and forms affecting the sense organ—create the point of contact between our mind and the world outside our mind. That contact generates feelings—not feelings in the sense of emotion, but something more basic and primitive, but still with an affective component. What we feel, we perceive; i.e. we make contact with the world, and something, in that point of contact, at the moment of contact, attracts our attention. We notice it, we perceive it, i.e. we abstract it from an unnoticed (back)ground. What we notice/perceive, we reason about: we further abstract it, by categorizing it, theorizing about its history and origins, judging it against various standards of beauty, probability, worth, etc., assessing it in various ways—its size, weight, value, age, etc.

That momentary perceptual contact, being reasoned about, becomes papañca, a term I’ve translated, following Bhikkhu Ñaṇananda, as "proliferation". That is, the perceived contact, reasoned about, becomes something large, something ugly, something expensive, something insignificant, etc. But always in relation to me, to I, to my sense of value, judgment, understanding, etc. And proliferation proliferates: concept leads to concept, notion to notion. Whenever, through inattention or inadequate mindfulness, papañca emerges, the proliferation of concepts and imaginings takes over. There is no limit to how many past forms we can derive from our perception, how far into the future our imaginings can take us, or how many different ways we can multiply that momentary perceptual contact to maintain our illusory sense of an enduring present.

The result of papañca is that the mental universe we inhabit is entirely constructed by our minds, and we can share little of that with others (most of whom are trapped in their own papañca). Papañca thwarts compassion and creates the condition for clinging to views, to obsessing about the elaborate structures of poste and riposte that we build in our minds (what someone in an AA meeting once described as “creating the wreckage of the future”), and to something close to panic as we cast about, always in vain, for something solid on which we might ground this sense of self that we create.

In his explanation of the Buddha’s doctrine of papañca, Mahā Kaccāna dissects, at some length and in great detail, the chain of processes that occur in an experience that feels to us instantaneous and atomic, and of which we are not even usually conscious—the experience of engaging the world through our perceptual organs and our sense of that as an experience of reality. Mahā Kaccāna’s deconstruction of the process shows that the raw perceptual experience and the contingent experience of reality, although they feel identical, are quite different kinds of experience, the first emerging as an inevitable result of our having organs of perception and the world being full of perceivable things; the second emerging from unabandoned craving and the need to support the illusory self that is the essential object of that craving.

Papañca is, to my mind, one of the most difficult concepts expressed in the Suttas, and I’m not at all sure that I have it right. But the more I consider the concept and the more I ponder the meaning of the Madhupindika Sutta, the more convinced I am by the Buddha’s location of the roots of violence in papañca. In my rendering of the Sutta, I have chosen my terms after a good deal of consideration and have expanded some of the more telegraphic points just enough to help a modern audience, unfamiliar with the details of the Buddha’s doctrine, to understand those. I have also reduced some of the repetition in Mahā Kaccāna’s exposition, hopefully without diminishing the force or clarity of his argument.